JP6525733B2 - Fixing member and manufacturing method thereof, fixing device and electrophotographic image forming apparatus - Google Patents

Description

  The present invention relates to a fixing member used in an electrophotographic image forming apparatus and a method of manufacturing the same. The present invention also relates to a fixing device and an electrophotographic image forming apparatus.

  Generally, in a heating and fixing apparatus used for electrophotography such as copying machines and laser printers, rotating members such as a pair of rollers at least one of which is heated, a film and a roller, a belt and a roller, and a belt and a belt are pressed against each other There is.

  Then, a recording material (paper or the like) holding an image formed by the toner in the unfixed state is introduced into a pressure contact portion (fixing nip) formed between the rotating members. At this time, the heated rotating body heats the recording material to melt the toner and fix the image on the recording material.

  A rotating member in contact with an unfixed toner image held on a recording material is referred to as a fixing member, and is referred to as a fixing roller, a fixing film, a fixing belt or the like according to the form.

  Along with colorization and high image quality of the electrophotographic image forming apparatus, it is necessary to wrap and fuse and mix color toner in the fixing nip portion. Therefore, a fixing member having a structure in which a base material, an elastic layer containing silicone rubber and the like provided on the base material, and a release layer excellent in releasability containing a fluorine resin and the like are laminated in this order. Is used.

  By the way, for the fixing member having such a configuration, a high thermal conductivity is conventionally required. In order to meet such requirements, Patent Document 1 has a substrate formed of metal or resin, an elastic layer formed on the substrate, and a release layer formed on the elastic layer, A fuser belt is disclosed which comprises carbon fibers in a layer. Further, Patent Document 2 has a tube-shaped substrate, an elastic layer provided on the outer peripheral side of the substrate, and a surface layer provided on the outer peripheral side of the elastic layer, and the elastic layer is filled with a predetermined amount of filler. And a fixing belt containing carbon nanotubes.

JP, 2002-268423, A JP, 2010-92008, A

The present invention is a fixing member comprising a carbon nanotube and an elastic layer comprising a cured silicone rubber having sufficient elasticity, provided on a substrate, and wherein the substrate and the elastic layer have sufficient adhesion. And it aims at provision of the manufacturing method.
The present invention is also directed to the provision of a fixing device and an electrophotographic image forming apparatus which contribute to stable formation of a high quality electrophotographic image.

According to the present invention, a fixing member for electrophotography comprising a substrate, an elastic layer comprising a cured silicone rubber provided on the substrate, and a surface layer,
The elastic layer further comprises carbon nanotubes,
When the elastic modulus at 50 ° C. of the elastic layer is E50 and the elastic modulus at 200 ° C. of the elastic layer is E200, E200 / E50 is 0.5 or more and less than 1.0,
The peel adhesion strength between the elastic layer and the substrate is 3.0 N / cm or more and 20.0 N / cm or less, and the elastic layer has cohesive failure in the peeling test from the substrate. A fixing member is provided.

Further, according to the present invention, there is provided a method of manufacturing a fixing member as described above, comprising the step of curing a layer of an addition-curable silicone mixture formed on a substrate,
The addition-curable silicone mixture comprises a first silicone compound having an unsaturated aliphatic group bonded to a silicon atom in a side chain, a second silicone compound having a hydrogen atom bonded to a silicon atom, and a silicon atom bonded thereto. There is provided a method for producing a fixing member, which comprises the above-described third silicone compound having an unsaturated aliphatic group at its end, and a carbon nanotube.

  Further, according to the present invention, there is provided a fixing device for fixing an unfixed toner image formed on a recording medium onto a recording medium, wherein the fixing member is arranged to face the fixing member and the fixing member. A fixing device is provided which comprises a member and a pressure member forming a fixing nip.

  Further, according to the present invention, an electrophotographic photosensitive member, a charging device for charging the surface of the electrophotographic photosensitive member, an exposure unit for forming an electrostatic latent image on the electrophotographic photosensitive member, an intermediate transfer member, and the above fixing An electrophotographic imaging apparatus comprising the apparatus is provided.

FIG. 3 is a schematic cross-sectional view showing an aspect of the fixing member according to the present invention. FIG. 3 is a schematic cross-sectional view showing an aspect of the fixing member according to the present invention. It is a schematic diagram explaining the measuring method of the adhesive strength used by this invention. FIG. 2 is a schematic cross-sectional view showing a configuration of an example of a fixing device according to the present invention using a belt-shaped fixing member. FIG. 2 is a schematic cross-sectional view showing a configuration of an example of a fixing device according to the present invention using a roller-shaped fixing member. FIG. 1 is a schematic cross-sectional view showing the configuration of a color laser printer that is an aspect of an embodiment of an electrophotographic image forming apparatus according to the present invention.

  The present inventors examined forming an elastic layer by curing a liquid addition-curable silicone mixture containing carbon nanotubes. The liquid addition-curable silicone mixture generally comprises a first silicone compound having an unsaturated aliphatic group bonded to a silicon atom in the molecule, and a hydrogen atom bonded to the silicon atom. And a second silicone compound contained in the molecule as a basic component. Then, the unsaturated aliphatic group of the first silicone compound and the hydrosilyl group of the second silicone compound are reacted and cured to obtain a silicone rubber.

  Then, as a result of the above examination, the liquid addition-curable silicone mixture containing carbon nanotubes has a viscosity increased by containing carbon nanotubes, which hinders the formation of an elastic layer having a uniform film thickness. I found that I might come.

  Therefore, the present inventors examined reducing the molecular weight of the first silicone compound in order to suppress the increase in viscosity accompanying the addition of carbon nanotubes. In this case, lowering the molecular weight of the first silicone compound relatively reduces the elasticity of the silicone rubber after curing. On the other hand, when using a low molecular weight one as the first silicone compound, the inventors of the present invention have the unsaturated aliphatic group at the side in order to sufficiently develop the crosslinked structure in the silicone rubber after curing. It tried to use what was introduced in the chain. By reacting the unsaturated aliphatic group introduced into the side chain with the hydrosilyl group, the crosslinking density of the cured silicone rubber is improved to maintain the elasticity of the elastic layer. As a result, although the elasticity of the elastic layer is sufficiently maintained, adhesion between the base and the elastic layer is insufficient, and peeling may occur at the interface between the base and the elastic layer. We came to find an issue.

  As a result of investigations by the present inventors for the novel subject, as a result, an elastic layer containing a carbon nanotube and a cured silicone rubber having sufficient elasticity is provided on a substrate, and It came to obtain a fixing member having sufficient adhesiveness with the elastic layer.

The fixing member according to the present invention has a substrate, an elastic layer including a cured silicone rubber provided on the substrate, and a surface layer, and the elastic layer further includes carbon nanotubes.
When the elastic modulus at 50 ° C. of the elastic layer is E50 and the elastic modulus at 200 ° C. of the elastic layer is E200, E200 / E50 is 0.5 or more and less than 1.0,
The peel adhesion strength between the elastic layer and the substrate is 3.0 N / cm or more and 20.0 N / cm or less, and the elastic layer has cohesive failure in the peeling test from the substrate. .

  Here, the elastic modulus E50 at 50 ° C. of the elastic layer assumes a case where the fixing member is placed in a relatively low temperature environment, and is a value at a temperature that is less likely to include variations and can be measured stably. . Further, the elastic modulus E200 at 200 ° C. is a maximum temperature at which deterioration due to decomposition or the like of the silicone rubber does not occur when the fixing member is actually used for heat fixing in the electrophotographic image forming apparatus. It is the value at the time of use. E200 / E50, which is the elastic modulus ratio at each temperature, indicates the degree of change in elastic modulus when the temperature of the fixing member changes from the standby state of the fixing device, that is, the so-called standby state to the actual use temperature environment. As this value is closer to 1.0, it can be said that the elastic layer exhibits stable elasticity independently of temperature in the actual use temperature environment of the fixing member. In other words, the value of E200 / E50 can also be referred to as an index indicating the degree of relative development of the crosslinked structure of the cured silicone rubber in the elastic layer. Therefore, when the first silicone compound having a large amount of unsaturated aliphatic groups introduced in the side chain is used, the crosslink density can be developed, so the value of E200 / E50 is set to 1.0. It is possible to adjust in the direction of approaching.

  Further, by setting the adhesive strength between the elastic layer and the base material at a temperature of 25 ° C. to 3.0 N / cm or more and 20.0 N / cm or less, the fixing member is attached to the fixing device and in a pressurized state. When put to practical use, the fixing member can have sufficient adhesive strength.

（式１中、ｍは０以上の整数、ｎは３以上の整数を示す。） The present inventors repeatedly studied the reason why the adhesion between the elastic layer containing the cured silicone rubber containing carbon nanotube and the base material is lowered and the interface peeling is likely to occur, and it is presumed as follows.
That is, the base material and the elastic layer containing the cured silicone rubber formed thereon have the unsaturated aliphatic group possessed by the first silicone compound in the addition-curable silicone mixture as a functional group on the surface of the base material. It adheres by reacting. Here, as the first silicone compound having an unsaturated aliphatic group bonded to a silicon atom in the addition-curable silicone mixture, a silicone having an unsaturated aliphatic group introduced into a side chain, as exemplified by the following formula 1 When a compound is used, many unsaturated aliphatic groups are in close proximity in the molecule, so carbon nanotubes interact with this unsaturated aliphatic group, and the unsaturated that can be involved in adhesion to the substrate The amount of aliphatic groups decreases.

(In the formula 1, m is an integer of 0 or more and n is an integer of 3 or more.)

（式２中、ｎは正の整数を示す。） Based on the above estimation, the present inventors contribute to the formation of a chemical bond with the substrate even in the presence of carbon nanotubes in the film of the liquid addition-curable silicone mixture formed on the substrate. Studies were conducted on the presence of unsaturated aliphatic groups. As a result, a third silicone compound represented by the following formula 2 in which two or more unsaturated aliphatic groups are separated by dimethylsiloxane chains may be further included in the addition-curable silicone mixture: I found it to be effective.

(In the formula 2, n represents a positive integer.)

  An elastic layer containing a cured silicone rubber formed by forming a layer of an addition-curable silicone mixture further containing the third silicone compound represented by the above formula 2 on a substrate and curing the layer is adhered to the substrate It is excellent in sex. As a result, the adhesive strength between the elastic layer and the base material is 3.0 N / cm or more and 20.0 N / cm or less, and the elastic layer is the base material when it is determined by the peeling test under the conditions described later. It does not separate at the interface with it, resulting in cohesive failure. The mechanism of action that makes it possible to secure the adhesive strength by using the third silicone compound has not been sufficiently elucidated yet, but the present inventors speculate as follows.

  That is, in the curing process of the addition-curable silicone mixture by the hydrosilylation reaction, the third silicone compound having an unsaturated aliphatic group at the end causes one of the unsaturated aliphatic groups in the molecule to interact with the carbon nanotube, Even when it becomes impossible to contribute to the reaction with the substrate, the other unsaturated aliphatic group present at a distant position can have relatively free molecular mobility, so the chemistry with the substrate can be avoided. It is believed that bonds can be formed. As a result, when a peel test is performed between the substrate and the elastic layer, the interface between the substrate and the elastic layer does not exhibit separation (adhesion failure), and adhesion is sufficient to a level at which cohesive failure of the elastic layer occurs. It is considered that a fixing member exhibiting strength can be obtained.

1. Fixing Member Next, the fixing member according to the present invention will be described in detail based on the specific configuration.

  The fixing member according to the present invention is a fixing member for electrophotography having a substrate, an elastic layer and a surface layer. The elastic layer contains cured silicone rubber as a base material and contains carbon nanotubes as a filler. The ratio of the elastic modulus E50 at 50 ° C. of the elastic layer to the elastic modulus E200 at 200 ° C., E200 / E50, is 0.5 or more and less than 1.0. The adhesive strength between the elastic layer and the substrate at a temperature of 25 ° C. is 3.0 N / cm or more and 20.0 N / cm or less. The elastic layer is characterized by cohesive failure during the peel test.

(1) Fixing Member FIGS. 1A and 1B are schematic cross-sectional views showing an embodiment of the fixing member according to the present invention, wherein 1 is a fixing member in the form of a belt (so-called fixing belt) and 2 is a fixing in the form of a roller. 2 shows a member (so-called fixing roller). Generally, the substrate itself is deformed, and when it is used to form a fixing nip, it is called a fixing belt, and the substrate itself is hardly deformed, and when the fixing nip is formed by elastic deformation of an elastic layer It is called a roller.
In FIG. 1, 3 is a base material, 4 is an elastic layer covering the peripheral surface of the base material 3, and 5 is a surface layer covering the peripheral surface of the elastic layer 4. The surface layer 5 may be fixed to the circumferential surface of the elastic layer 4 by an adhesive layer (not shown).

(2) Base Material As a material of the base material 3, for example, a metal or alloy such as aluminum, iron, stainless steel or nickel, or a heat resistant resin such as polyimide is used.

  When the fixing member has a roller shape, a core metal is used for the base 3. As a material of a core metal, metals and alloys, such as aluminum, iron, stainless steel, are mentioned, for example. At this time, even if the inside of the cored bar is hollow, it only needs to have a strength to withstand the pressure in the fixing device. In the case of the hollow shape, it is also possible to provide a heat source inside.

  When the fixing member has a belt shape, examples of the substrate 3 include a heat-resistant resin belt made of an electroformed nickel sleeve, a stainless steel sleeve, a polyimide or the like. The inner surface may be further provided with a layer (not shown) for imparting functions such as abrasion resistance and heat insulation.

  The outer surface of the substrate 3 may be subjected to surface treatment to impart a function such as adhesion with the elastic layer 4. The surface treatment may be physical treatment such as blast, lapping or polishing, or chemical treatment such as oxidation treatment, coupling agent treatment, or primer treatment, and these may be used in combination.

  In particular, when silicone rubber is used as the elastic layer 4, primer treatment is generally used as surface treatment. The primer used here is appropriately compounded in an organic solvent with a silane coupling agent, a silicone compound, methyl hydride hydride, alkoxysilane, a catalyst for promoting reaction such as hydrolysis / condensation / addition, a coloring agent such as bengara, etc. It is in the form of a dispersed paint. These are commercially available. Such a primer is applied to the surface of the substrate 3 (adhesion surface with the elastic layer 4), and is subjected to a primer treatment through a process of drying and baking.

  The primer can be appropriately selected depending on the material of the substrate 3, the type of the elastic layer 4, the reaction form at the time of crosslinking, and the like. For example, when the elastic layer 4 contains a large amount of unsaturated aliphatic groups, in order to impart adhesiveness by reaction with the unsaturated aliphatic groups, a primer containing a hydrosilyl group is suitably used as a primer. In addition, when the elastic layer 4 contains a large amount of hydrosilyl groups, conversely, those containing unsaturated aliphatic groups are suitably used as the primer. In addition, those containing an alkoxy group can be appropriately selected according to the types of the substrate 3 and the elastic layer 4 which are adherends.

(3) Elastic Layer The elastic layer 4 does not excessively crush the toner at the time of fixing, and functions as a layer that causes the fixing member to bear an elasticity that follows the unevenness of the paper fibers.

  In order to develop such a function, silicone rubber is used as the base material for the elastic layer 4, and it is preferable to cure the liquid addition-curable silicone mixture among them. This is because it is easy to disperse the filler (filler) because there are many in the liquid state, and the elasticity can be adjusted by adjusting the degree of crosslinking according to the type and amount of filler described later. is there.

As the addition-curable silicone mixture, a silicone compound (first silicone compound) having an unsaturated aliphatic group which functions as a crosslinking point at the time of curing reaction is used as a base material.
In this base material, a silicone compound (second silicone compound) having a plurality of silicon atom-bonded hydrogen groups (hydrosilyl group) in the molecule, and a silicone compound (third silicone) having an unsaturated aliphatic group at the end of the molecular chain Compound) and carbon nanotubes as a filler are blended.
Furthermore, a catalyst for accelerating the hydrosilylation reaction in the addition-curable silicone mixture, a reaction control agent (inhibitor) called an inhibitor for controlling the reaction initiation time, or the like may be blended.
As the catalyst, generally known materials such as platinum compounds and rhodium compounds are used. As the reaction control agent, known substances such as methyl vinyl tetrasiloxane, acetylene alcohols, siloxane-modified acetylene alcohol, hydroperoxide and the like are used.

  Furthermore, in addition to these, a silicone rubber composition can be obtained by kneading and dispersing a filler called a filler such as a carbon nanotube in order to impart thermal conductivity, heat resistance, reinforcing property and the like.

  The silicone rubber composition thus obtained is supported on the outer peripheral surface of the substrate 3 by processing methods such as mold molding method, blade coat method, nozzle coat method, ring coat method and the like by a method such as heating. By advancing the crosslinking reaction, it is possible to form the elastic layer 4.

The thickness of the elastic layer 4 can be appropriately designed from the viewpoint of the contribution to the surface hardness of the fixing member and the securing of the nip width.
When the fixing member has a belt shape (hereinafter, fixing belt), the preferable range of the thickness of the elastic layer 4 is 100 μm or more and 500 μm or less, more preferably 200 μm or more and 400 μm or less. This is because the nip width can be secured by the deformation of the base 3 when incorporated in the fixing device. Further, in the heat fixing apparatus, a heater is often disposed inside the fixing belt. In this case, the elastic layer having the above-described thickness range is unlikely to inhibit heat conduction from the back surface side to the front surface side of the fixing belt.
When the fixing member has a roller shape, the base 3 is a rigid body, and the nip width needs to be formed by the deformation of the elastic layer 4. Therefore, the preferable range of the thickness of the elastic layer 4 is 300 μm or more and 10 mm or less, more preferably 1 mm or more and 5 mm or less.
The adhesive strength between the elastic layer 4 formed on the outer peripheral surface of the substrate 3 and the substrate 3 will be described in detail later.

(3-1) First silicone compound (silicone compound having unsaturated aliphatic group)
As described above, when carbon nanotubes are compounded as a filler, the structural viscosity of the silicone rubber composition increases due to its fibrous form. For this reason, it is important to use a polymer having a relatively low viscosity, that is, a small molecular weight, as the silicone compound having an unsaturated aliphatic group used for the base material of the silicone rubber composition. Since silicone compounds are high molecular weight compounds, it is difficult to uniquely identify their molecular weight, but their constitution can be confirmed by using a weight average molecular weight (Mw) measured by gel permeation chromatography (GPC). It is. Specifically, those having a weight average molecular weight of 150,000 or less are preferable, and those having a weight average molecular weight of 70,000 or less are more preferable. If the molecular weight is larger than this, the structural viscosity of the silicone rubber composition becomes very high, and the molding process becomes extremely difficult.

（式３中、Ｒ_１及びＲ_２は後述する。ｍは０以上の整数、ｎは３以上の整数を示す。） As the unsaturated aliphatic group to be introduced into such a silicone compound, by being introduced into the side chain moiety R ₂ as shown by the following formula 3, it becomes possible to introduce many into one molecule, When subjected to a crosslinking reaction with the crosslinker silicone compound, the elastic layer exhibits a stable elasticity with little influence of temperature change.
-Formula 3 Structural formula of the silicone compound which has unsaturated aliphatic group in a side chain

(In Formula 3, R ₁ and R ₂ will be described later. M is an integer of 0 or more, n is an integer of 3 or more.)

In Formula 3, R ₁ represents a monovalent unsubstituted or substituted hydrocarbon group bonded to a silicon atom and not containing an unsaturated aliphatic group. Specific examples include the following.
An alkyl group (eg, methyl, ethyl, propyl, butyl, pentyl, hexyl etc.);
An aryl group (such as a phenyl group);
-A substituted hydrocarbon group (for example, chloromethyl, 3-chloropropyl, 3,3,3-trifluoropropyl, 3-cyanopropyl, 3-methoxypropyl and the like).

In particular, easy to synthesize and handling since excellent heat resistance can be obtained, it is preferable that 50% or more of R ₁ is a methyl group, and particularly preferably all of R ₁ is a methyl group.

Further, R ₂ represents an unsaturated aliphatic group bonded to a silicon atom, and examples thereof include a vinyl group, an allyl group, a 3-butenyl group, a 4-pentenyl group and a 5-hexenyl group, which are easy to synthesize and handle. The vinyl group is preferred because it is inexpensive and the crosslinking reaction is easily carried out.

  The presence of the silicone compound having a vinyl group in the side chain portion can be confirmed by performing hydrogen nucleus measurement (H-NMR) using a nuclear magnetic resonance apparatus (NMR). Since the three hydrogen atoms present in the side chain vinyl group are not equivalent to each other, they are spin-coupled to each other, so the assigned peaks are from the lower chemical shift side at 5.74, 5.76, 5.79,5 Separately detected at .80, 5.88, 5.90, 5.92, 5.93, 5.94, 5.98, 5.99, 6.03 ppm. The peaks separated and detected due to such chemical shifts are characteristic of vinyl groups introduced into the side chain portion of the first silicone compound.

（式５中、Ｒ_１は後述する。ｍは０以上の整数、ｎは３以上の整数を示す。）

（式６中、Ｒ_１は後述する。ｍは０以上の整数、ｎは３以上の整数を示す。） (3-2) Second Silicone Compound The second silicone compound which functions as a crosslinking agent to be used by being added to the addition-curable silicone rubber has a plurality of silicon atom-bonded hydrogen groups (hydrosilyl groups) in the molecule. Silicone compounds can be used. The crosslinker silicone compound has a siloxane structure in which a silicon atom and an oxygen atom are bonded as a main chain structure, and its molecular skeleton may be linear, branched or cyclic, and a mixture thereof May be used. An example of a linear crosslinking agent silicone compound is shown in the following formula 5, and an example of a cyclic crosslinking agent silicone compound is shown in the following formula 6.

(In Formula 5, R ₁ will be described later. M is an integer of 0 or more and n is an integer of 3 or more.)

(In Formula 6, R ₁ will be described later. M is an integer of 0 or more, n is an integer of 3 or more.)

In Formula 5 and Formula 6, R ₁ is a monovalent unsubstituted or unsaturated aliphatic group-free or non-unsaturated aliphatic group bonded to a silicon atom, similar to R ₁ described in the section on silicone compounds having an unsaturated aliphatic group. Represents a substituted hydrocarbon group.

In particular, easy to synthesize and handling, since the excellent heat resistance can be obtained, it is preferable that 50% or more of R ₁ is a methyl group, and particularly preferably all of R ₁ is a methyl group.

With regard to the presence of the second silicone compound having a silicon-bonded hydrogen group (hydrosilyl group), when R ₁ is all methyl groups, hydrogen using a nuclear magnetic resonance apparatus (NMR) for hydrogen atoms of the hydrosilyl group This can be confirmed by nuclear measurement (H-NMR). The chemical shift attributed to the hydrogen atom of the hydrosilyl group in this case changes somewhat depending on the environment of the silicon atom directly connected, but a peak appears at a position centered on 4.65 to 4.70 ppm. The amount of hydrosilyl group can be calculated by measuring the integrated value of this portion.

(3-3) Third Silicone Compound Further, in the present invention, as a component for improving the adhesion between the substrate 3 and the elastic layer 4 in the liquid addition-curable silicone mixture, the end of the molecular chain is unsaturated. It is important to contain a silicone compound having an aliphatic group.

  The unsaturated aliphatic group introduced to the side chain in the first silicone compound reduces the proportion that can contribute to the adhesion to the substrate 3 by the interaction with the carbon nanotube, so the adhesion strength is reduced. It is guessed.

  However, by containing a third silicone compound having an unsaturated aliphatic group at the end of the molecular chain, an unsaturated aliphatic group that contributes to the formation of a chemical bond with the substrate 3 is formed on the substrate 3 Can be present in the layer of the addition-curable silicone mixture. As a result, it is possible to secure sufficient adhesion between the substrate 3 and the elastic layer 4.

  In the third silicone compound, since the unsaturated aliphatic groups in the molecule are separated by the dialkylsiloxane chain and located at remote positions, the unsaturated aliphatic group in the molecule simultaneously interacts with the carbon nanotube It is thought that the probability of doing so is low and the proportion contributing to the adhesion reaction with the substrate 3 is increased. As a result, the adhesion between the substrate 3 and the elastic layer 4 is improved, and sufficient adhesion durability can be obtained.

（式４中、Ｒ_１及びＲ_２は後述する。ｎは正の整数を示す） The unsaturated aliphatic group in the third silicone compound is introduced into the terminal portion R ₂ of the molecular chain as shown in the following formula 4.

(In Formula 4, R ₁ and R ₂ will be described later. N is a positive integer.)

In the formula 4, the structure of the R ₁ and R _2, appearing in equation 3 has the same meaning as R ₁ and R ₂ exemplified for the silicone compound having an unsaturated aliphatic group in the side chain.
A methyl group is preferable as R _{1 and a} vinyl group is preferable as R ₂ . n represents a positive integer. Here, the number of n in Formula 4 determines the distance between unsaturated aliphatic groups represented by R ₂ located at both ends of the molecule. And, in the present invention, even when one unsaturated aliphatic group is trapped by the interaction with the carbon nanotube, the molecular mobility of the other unsaturated aliphatic group is not impaired. It is preferable to separate the unsaturated aliphatic groups sufficiently. Therefore, n in the formula 4 is preferably 50 or more, and particularly preferably 200 or more. Further, in order to avoid excessively raising the viscosity of the liquid addition-curable silicone mixture, the number of n in the formula 4 is preferably 2000 or less, and particularly preferably 1000 or less.

As to the presence of the third silicone compound having a vinyl group as an unsaturated aliphatic group at the terminal part, hydrogen nuclear measurement (H-NMR) was also measured using a nuclear magnetic resonance apparatus (NMR) in the same manner as described above. It can be confirmed by doing.
The three hydrogen atoms present in the terminal vinyl group are also each nonequivalent. Thus, although spin coupling occurs to each other, the chemical shift of the peak appears at a position different from that of the side chain structure. The peaks attributed to the terminal vinyl group are 5.68, 5.69, 5.73, 5.75, 5.89, 5.90, 5.92, 5.93, 6.06, from the lower chemical shift side. 6.10, 6.11, 6.15 ppm are respectively separated and detected. The peaks separated and detected due to such chemical shifts are characteristic of vinyl groups introduced into the terminal portion of the silicone compound.

  In the present invention, the proportion (molar fraction) of the terminal unsaturated aliphatic group possessed by the third silicone compound in the total amount of unsaturated aliphatic groups contained in the addition-curable silicone mixture according to the present invention is 1 It is preferable to set it as% or more and 30% or less. It is because the adhesiveness of the base material 3 and the elastic layer 4 can be made more favorable, maintaining the intensity | strength as an elastic layer sufficiently, for the crosslinking density of the silicone rubber in the elastic layer 4 to be sufficient.

The proportion (molar fraction) of the hydrosilyl group in the base polymer composed of the first to third silicone compounds to the silicon atom in the base polymer is 0.3 to 10.0 mol%, in particular, 0.1. 5-4.0 mol% is preferable.
Further, the ratio (molar fraction) of unsaturated aliphatic groups in the base polymer composed of the first to third silicone compounds to silicon atoms in the base polymer is 0.5 to 10.0 mol%, In particular, it is preferable to set it as 0.8-5.0 mol%.
Furthermore, the ratio of the amount of hydrosilyl groups to the amount of unsaturated aliphatic groups in the base polymer (number of moles of hydrosilyl groups / number of moles of unsaturated aliphatic groups) is 0.3 to 2.0, particularly And 0.5 to 1.0 are preferable.

When a vinyl group is used as the unsaturated aliphatic group, the ratio of the terminal vinyl group to the total amount of vinyl groups contained in the silicone rubber composition is quantified by using the above-mentioned H-NMR. Is possible. The total amount of vinyl groups is derived by setting the integrated value of 5.6 to 6.2 ppm to 1/3 (because there are three hydrogen atoms in the vinyl group).
Then, the peaks of 6.06, 6.10, 6.11, 6.15 ppm, which were separated into quartets by spin coupling of protons of terminal vinyl groups, became independent without overlapping with the proton chemical shift of side chain vinyl groups. Therefore, the integrated value of this portion is taken as the amount of terminal vinyl group because it can be detected. Thereby, the ratio of the terminal vinyl group to the total amount of vinyl groups can be calculated.

(3-4) Filler
The elastic layer 4 contains carbon nanotubes as a filler for imparting thermal conductivity. Carbon nanotubes are manufactured by methods such as arc method, laser ablation method, DIPS method (Direct Injection Pyrolytic Synthesis method), CoMoCAT method, HiPCO method, super growth CVD method, vapor phase growth method, etc. is there. Among them, carbon nanotubes produced by a vapor phase growth method are particularly preferable in terms of shape controllability and dispersibility in a silicone compound.

The carbon nanotubes of the vapor phase growth method are obtained by using a hydrocarbon and hydrogen as raw materials, performing a thermal decomposition reaction in the gas phase in a heating furnace, and growing the catalyst fine particles into a fibrous form using nuclei. The fiber diameter and fiber length are controlled by the type, size and composition of the raw material and catalyst, reaction temperature, pressure and time, etc., and after the reaction, a material in which the graphite structure is further developed by heat treatment is known. It has a multilayer structure in the radial direction of the fiber, and has a shape in which a graphite structure is laminated in a cylindrical shape. This graphite structure exhibits a very sharp absorption around 1570-1580 cm ⁻¹ when measuring Raman spectrophotometry, so its presence can be confirmed.

Other fillers may be blended in the elastic layer 4 in order to further impart thermal conductivity. Specific examples of the filler used for the purpose of imparting thermal conductivity include the following examples.
Silicon carbide (SiC); silicon nitride (Si ₃ N ₄ ); boron nitride (BN); aluminum nitride (AlN); alumina (Al ₂ O ₃ ); zinc oxide (ZnO); magnesium oxide (MgO); silica (SiO 2) ₂ ); copper (Cu); aluminum (Al); silver (Ag); iron (Fe); nickel (Ni); silicon (Si); carbon fiber (C) and the like.
These can be used alone or in combination of two or more.

  The average particle diameter of the heat conductive filler is preferably 1 μm or more and 50 μm or less from the viewpoint of handling and dispersibility. The shape is spherical, crushed, needle-like, plate-like, whisker-like, etc., but spherical one is preferable from the viewpoint of dispersibility.

In addition, for the purpose of imparting properties such as reinforcement, heat resistance, processability, conductivity etc. as a filler, iron oxide (FeO · Fe ₂ O ₃ · Fe ₃ O ₄ ) or titanium oxide (TiO ₂ ) in a small amount ₂ ) Carbon black (C) etc. may be included. Furthermore, it may contain silica (SiO ₂ ) for this purpose.

The filler in the addition-curable silicone mixture is blended in an amount necessary for the elastic layer to have the elastic modulus (E50, E200) described later. Specifically, the carbon nanotube is in the range of 0.5 to 15 % by volume in volume filling ratio with respect to the mixture (base polymer) of the first silicone compound, the second silicone compound and the third silicone compound. It is preferable to adjust appropriately within.
In addition, the other filler such as alumina is 0 to 50% by volume, particularly, in terms of volume filling ratio with respect to the mixture of the first silicone compound, the second silicone compound and the third silicone compound (base polymer). It is preferable to adjust suitably within the range of 10-40 volume%.

(3-5) Elastic modulus of elastic layer The fixing member is used in a heated state to melt the toner, but it is important from the viewpoint of stability of the fixing image quality that the elastic change is small in the use temperature range. About this, it becomes possible to compare and evaluate whether stable elasticity can be secured by measuring the temperature dependency of the elastic modulus change of the elastic layer 4 in the use temperature range of the fixing member.

  Specifically, a sample (length 50 mm, width 5 mm, thickness 2 mm) cut from the elastic layer 4 of the fixing member is prepared. After setting a sample of this elastic layer 4 in a dynamic viscoelasticity measuring apparatus (DMA) equipped with a heating furnace, the vibration frequency is set to 10 Hz, and the temperature condition is changed to measure, thereby the elasticity at each temperature It is possible to measure the rate.

  In particular, the ratio of the elastic modulus E50 at 50 ° C. of the elastic layer 4 to the elastic modulus E200 at 200 ° C., E200 / E50 of 0.5 or more and less than 1.0 is for stable image quality assurance. It is necessary to

Here, the elastic modulus E50 at 50 ° C. is assumed to be in a relatively low temperature environment as a fixing member, and is a value at a temperature that is less likely to include variations and can be measured stably.
On the other hand, the elastic modulus E200 at 200 ° C. is a value at the highest temperature at which deterioration due to decomposition or the like of the silicone rubber does not occur within a range assuming the actual use environmental temperature of the fixing member.
The elastic modulus ratio “E200 / E50” at each temperature indicates the degree of change in elastic modulus when the temperature of the fixing member changes from the standby state of the fixing device, that is, the so-called standby state to the actual use temperature environment. As this value approaches 1.0, it can be said that the elastic layer 4 exhibits a stable elasticity independently of the temperature in the actual use temperature environment of the fixing member.

  As described above, the elasticity after curing is changed by changing the type, molecular weight, cross-linked structure, number of cross-linking points, and further the type and amount of filler in the mixing step of the raw materials of the silicone rubber composition. The modulus of elasticity of layer 4 is controlled.

  However, in the addition-curable silicone mixture in which carbon nanotubes are blended as a filler, it is necessary to use a silicone compound having a relatively low molecular weight because structural viscosity is strongly generated. At this time, if a silicone compound having an unsaturated aliphatic group at the end is blended in a large amount, the branched structure in the base polymer is not developed, and the development of the branched structure of the cured elastic layer 4 is hindered. As a result, the temperature dependence of the elastic modulus in the elastic layer 4 becomes large, and the ratio of elastic modulus E200 / E50 becomes a value below 0.5.

  That is, in the elastic layer 4 containing carbon nanotubes, a branched / crosslinked structure is developed by mainly containing a silicone compound having an unsaturated aliphatic group in the side chain as the silicone compound component in the silicone rubber composition. The temperature dependence of the elastic modulus needs to be reduced. Here, the term "mainly compounding" means that the content of the component is the largest in terms of weight among all the components of the silicone compound component constituting the silicone rubber composition, and in particular, the component is 50% by weight in the total components. It is preferable to include the above.

  E50 and E200 according to the present invention is preferably in the range of 0.5 MPa or more and 4.5 MPa or less as a measure of the flexibility that the elastic layer 4 of the fixing member should have. More specifically, E50 is preferably in the range of 1.7 MPa or more and 4.5 MPa or less, and E200 is preferably in the range of 0.7 MPa or more and 2.8 MPa or less.

  And the elastic layer 4 which satisfies the condition that the values of E50 and E200 are respectively in the above range and E200 / E50 is 0.5 or more and less than 1.0, has elasticity to be provided as an elastic layer. In addition, it can be said that it is composed of a silicone rubber having a strong crosslinked structure which is not easily broken even at a temperature of 200.degree.

  By the way, the elastic layer 4 according to the present invention has a tensile strength (TS) of at least 0.4 MPa when measured using a dumbbell-shaped No. 3 test piece based on Japanese Industrial Standard (JIS) K 6251: 2010. And 3.0 MPa or less, particularly preferably 1.0 MPa or more and 2.5 MPa or less. The tensile strength of the elastic layer 4 is mainly governed by the degree of crosslinking of the silicone rubber, as well as the elastic modulus. Therefore, the elastic layer 4 in which E50 and E200 are within the above-mentioned numerical range basically has a tensile strength within the above-mentioned range.

(4) Surface Layer As the surface layer 5, a fluorocarbon resin layer, for example, resins exemplified below are used singly or in combination. Tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer (PFA), polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP) and the like.
Among the materials listed above, PFA is preferable from the viewpoint of moldability and toner releasability.

  It does not specifically limit as a formation method. For example, a method of coating a tube-shaped one on the elastic layer 4 through an adhesive layer (not shown), or one in which fine particles of a fluorine resin are directly or dispersed in a solvent is formed into an elastic layer 4 After coating on the surface, drying, melting and baking may be mentioned.

  In addition, a filler may be contained in the surface layer 5 in order to control the thermophysical properties within a range that does not impair the moldability and the releasability.

  The thickness of the surface layer 5 is preferably 50 μm or less, and more preferably 30 μm or less. When the surface layer 5 is laminated, the elasticity of the elastic layer 4 can be maintained, and the surface hardness of the fixing member can be suppressed from being too high.

(5) Adhesive strength between substrate and elastic layer, and peeling test Adhesive strength between substrate 3 and elastic layer 4 at 25 ° C. is 3.0 N / cm or more and 20.0 N / cm or less is there. In the present invention, the adhesive strength between the substrate 3 and the elastic layer 4 is measured by the "adhesive-peel adhesive strength test method" (JIS K6854-1: 1999) defined by the Japanese Industrial Standard.

  A specific method of measuring adhesive strength will be described with reference to FIG. As necessary, the core 12 is inserted inside the fixing member 11 (in the figure, the fixing member in the form of a belt, ie, the fixing belt) so that the shape of the base of the fixing member 11 does not deform. Using a razor, make a slit 1 cm wide to reach the substrate surface from the elastic layer side. Next, a notch is made in the longitudinal direction of the fixing member 11 in the slitted part, and the surface layer is forcibly separated by about 2 cm in the circumferential direction from the interface between the elastic layer and the substrate using a razor. The tip end portion of the force gauge 13 is held in the chuck portion 14 of the force gauge 13. If the surface layer is thin and plastic deformation occurs, a reinforcing polyimide tape may be attached to the surface of the surface layer prior to the formation of the slit, and the slit may be formed thereon. This can suppress plastic deformation of the surface layer.

  Then, the core 12 (or the base material) is fixed so that the fixing member 11 can freely rotate in the circumferential direction, and the force gauge 13 is fixed using a means (not shown) at the root of the fixing member 11 at the root In a direction perpendicular to the tangential direction, pulling up is performed at a speed of 50 mm / min until the length of the layer on the peeled elastic layer side is 50 mm. This length is also called "peeling length".

  At this time, it is important that the peeling direction F is maintained at 90 ° with respect to the tangential direction of the fixing member main body at the root of the peeling end. In order to maintain 90 °, first, when the peeled end is sandwiched with a force gauge, the layer on the peeled elastic layer side is sandwiched so as to be 90 ° with respect to the tangential direction. Next, the force gauge 13 is pulled at 50 mm / min in the vertical direction F from directly above the rotation axis of the core 12 so that the moving speed at the tangent of the core 12 becomes equal to the moving speed in the vertical direction F , The core 12 is rotated in the direction of R in the figure. Specifically, when the outer diameter of the fixing belt is 30 mm, the peeling direction is maintained at 90 ° with respect to the tangential direction of the fixing member 11 by setting the rotational speed of the core to 0.53 rpm. be able to. The above measurements yield a force-grab travel distance curve over a 50 mm peel length. Then, from the force-gripping distance curve, an arithmetic mean value of the peeling force is determined. This value is taken as the "peel force" at one measurement point. Here, for the calculation of the arithmetic mean value of the peeling force, a force for every 0.1 mm of the gripping movement distance was used.

  In the adhesion strength in each example and comparative example to be described later, the peeling test was performed at any five places where the measurement results do not interfere with each other for the fixing members according to each example and each comparative example. Then, the arithmetic mean value of the "peel force" determined from the measurement results at the above five locations is taken as the "peel force" of the fixing member according to each example and comparative example. In the case of a fixing member in which the peeling length can not be 50 mm in the peeling test at one place, the peeling test is performed at a plurality of points so that the total peeling length is 250 mm, and the force-gripping movement is performed. A distance curve is created, an average peeling force is determined from the force-gripping movement distance curve, and this value is taken as the "peeling force" of the fixing member.

In addition, the fractured surface formed by this peeling test is judged in accordance with "adhesive-name of major failure mode" (JIS K 6686: 1999) defined by Japanese Industrial Standards. Then, the state in which the broken elastic layer is attached to the entire surface on the substrate side is determined as cohesive failure (CF) of the elastic layer.
On the other hand, when no elastic layer adheres to the substrate side at all, it is regarded as adhesive failure (interface peeling).
When the elastic layer adheres to a part of the substrate side, when the coverage of the broken elastic layer is 50% or more with respect to the peeling area of the elastic layer in the substrate, the cohesive failure of the elastic layer judge. Moreover, when the coverage of the fractured elastic layer is less than 50% with respect to the peeling area of the elastic layer in a base material, it determines with adhesive failure (interface peeling).

2. Fixing Device The fixing device according to the present invention has the above-described fixing member. In the fixing device, rotating members such as a pair of rollers at least one of which is heated, a film and a roller, a belt and a roller, and a belt and a belt are in pressure contact with each other. These rotating members are appropriately selected in consideration of conditions such as the process speed and the size of the entire image forming apparatus. Here, a specific example of a fixing device for fixing an unfixed toner image on a recording medium will be described, and the configuration thereof will be described.

(1) Fixing Device Using Belt-Shaped Fixing Member FIG. 3 is a schematic cross-sectional view of an example of the fixing device using the belt-shaped fixing member.
In this fixing device, the fixing belt 1 is a belt of a seamless shape (endless shape) as a fixing member according to the present invention. In order to hold the fixing belt 1, a belt guide member 16 molded of a heat-resistant, heat-insulating resin is disposed.
A ceramic heater 17 as a heat source is provided at a position where the belt guide member 16 contacts the inner surface of the fixing belt 1.
The ceramic heater 17 is fixedly supported by being fitted into a groove provided along the longitudinal direction of the belt guide member 16 (the rotational axis direction of the fixing belt 1). The ceramic heater 17 is energized by means (not shown) to generate heat.
The fixing belt 1 having a seamless shape is loosely fitted around the belt guide member 16. The pressurizing rigid stay 18 is inserted inside the belt guide member 16.
The elastic pressure roller 19 as a pressure member has a stainless steel core metal 19a provided with an elastic layer 19b of silicone rubber to reduce the surface hardness.
Both ends of the cored bar 19a are rotatably supported by bearings between the front and rear chassis side plates (not shown).
The elastic pressure roller 19 is coated with a 50 μm-thick fluorocarbon resin tube as a surface layer 19 c in order to improve surface properties and releasability.
A pressing force (not shown) is compressed between both ends of the pressing rigid stay 18 and a spring receiving member (not shown) on the apparatus chassis side to press down the pressing rigid stay 18 (FIG. 3). Downward force) is applied. As a result, the lower surface of the ceramic heater 17 disposed on the lower surface of the belt guide member 16 and the upper surface of the elastic pressure roller 19 are pressed against each other across the fixing belt 1 to form a fixing nip N having a predetermined width.
The recording medium P as the object to be heated, on which an image is formed by the unfixed toner G at the fixing nip N, is nipped and conveyed at a conveying speed V. Thus, the toner image is heated and pressurized. As a result, the toner image is melted and mixed, and then cooled to fix the toner image on the recording medium P.
In the fixing device according to the embodiment shown in FIG. 3, the elastic pressure roller 19 is rotated in the counterclockwise direction by being rotationally driven by a drive unit (not shown). The fixing belt 1 in contact with the fixing nip N is rotated in a clockwise direction as the elastic pressure roller 19 rotates.

(2) Fixing Device Using Fixing Member in Roller Shape FIG. 4 is a schematic cross-sectional view in a transverse direction of an example of the fixing device using the fixing member in the roller shape.
In this fixing device, the fixing roller 2 is a fixing member according to the present invention. In the fixing roller 2, an elastic layer 4 is formed on the outer peripheral surface of the base material 3, and a surface layer 5 is formed on the outer side of the elastic layer 4. Further, in the elastic pressure roller 19, an elastic layer 19b is formed on the outer peripheral surface of the core metal 19a, and a surface layer 19c is further formed on the outer side thereof.
An elastic pressure roller 19 as a pressure member is disposed so as to face the fixing roller 2, and two rollers are rotatably pressed by a pressure unit (not shown), thereby forming a fixing nip N. It is done. The pressing means may press one of the two rollers in the direction of the other fixed roller, or press the two rollers in the direction in which they face each other. May be
The insides of the fixing roller 2 and the elastic pressure roller 19 are hollow. A heater 20 as a heat source for supplying heat necessary for melting the unfixed toner G is provided in the hollow interior. A halogen heater is generally used as the heater 20. In some cases, a plurality of halogen heaters may be installed inside according to the size of the recording medium P being conveyed.
Rotational force is applied to at least one of the fixing roller 2 and the elastic pressure roller 19 through the end of the base 3 and the core metal 19a by means not shown, and the moving speed of the surface of the fixing roller 2 is the conveyance speed of the recording medium P The rotation is controlled to be approximately the same speed as V. At this time, the rotational force may be applied to either one of the fixing roller 2 and the elastic pressure roller 19, and the other may be rotated by the following or rotational force may be applied to both.
The recording medium P on which an image is formed by the unfixed toner G is nipped and conveyed at the fixing nip N of the fixing device formed as described above. Thereby, the unfixed toner image is heated and pressurized. As a result, the unfixed toner image is melted and mixed, and then cooled, whereby the toner image is fixed on the recording medium P.

3. Electrophotographic Image Forming Apparatus As an electrophotographic image forming apparatus according to the present invention, there are a multi-function machine using an electrophotographic method, a copier, a facsimile, and a printer. Here, using a color laser printer as an example, an outline of the entire configuration of the image forming apparatus of the present invention will be described.
FIG. 5 is a schematic cross-sectional view of a color laser printer which is an aspect of the embodiment of the electrophotographic image forming apparatus according to the present invention. The color laser printer (hereinafter referred to as "printer") 40 shown in FIG. 5 has a drum shape that rotates at a constant speed for each color of yellow (Y), magenta (M), cyan (C) and black (K). It has an electrophotographic image forming section having an electrophotographic photosensitive member (hereinafter referred to as "photosensitive drum"). The image forming apparatus further includes an intermediate transfer member 38 that holds a color image developed and multiply transferred in the electrophotographic image forming unit and further transfers the color image to the recording medium P fed from the feeding unit. The photosensitive drums 39 (39Y, 39M, 39C, 39K), which are electrophotographic photosensitive members, are rotationally driven counterclockwise as shown in FIG. 5 by driving means (not shown).

  Around the photosensitive drum 39, a charging device 21 (21Y, 21M, 21C, 21K) for charging the surface of the photosensitive drum 39 uniformly according to the rotation direction is irradiated with a laser beam based on image information, A scanner unit 22 (22Y, 22M, 22C, 22K) as an exposure unit that forms an electrostatic latent image on the photosensitive drum 39, and a developing unit 23 (toner image that develops toner as a toner image) 23Y, 23M, 23C, 23K), a primary transfer roller 24 (24Y, 24M, 24C, 24K) for transferring the toner image on the photosensitive drum 39 to the intermediate transfer member 38 at the primary transfer portion T1, the photosensitive drum after transfer 39 cleaning unit 25 (25Y, 25M, 25C, 2) having a cleaning blade for removing transfer residual toner left on the surface K) are arranged.

At the time of image formation, the belt-like intermediate transfer member 38 stretched around the rollers 26, 27 and 28 rotates, and each color toner image formed on each photosensitive drum 39 is superimposed on the above-mentioned intermediate transfer member 38 to form a primary image. A color image is formed by being transferred.
The recording medium P is conveyed to the secondary transfer portion T2 by the conveyance means in synchronization with the primary transfer onto the intermediate transfer body 38. The transport means has a feed cassette 29 accommodating a plurality of recording media P, a feed roller 30, a separation pad 31, and a registration roller pair 32. At the time of image formation, the feed roller 30 is driven to rotate according to the image forming operation, and the recording media P in the feed cassette 29 are separated one by one, and the registration roller pair 32 synchronizes with the image forming operation to make a secondary. Transport to the transfer unit T2.

  A movable secondary transfer roller 33 is disposed at the secondary transfer portion T2. The secondary transfer roller 33 is movable substantially in the vertical direction. Then, at the time of image transfer, the secondary transfer roller 33 is pressed against the intermediate transfer body 38 with a predetermined pressure via the recording medium P. At the same time, a bias is applied to the secondary transfer roller 33, and the toner image on the intermediate transfer member 38 is transferred to the recording medium P.

  Since the intermediate transfer member 38 and the secondary transfer roller 33 are respectively driven, the recording medium P in a state of being sandwiched between the two is conveyed at a predetermined conveyance speed V in the direction of the left arrow shown in FIG. The sheet is conveyed by the belt 34 to the fixing unit 35 which is the next process. The fixing unit 35 is a fixing device of the present invention. The fixing unit 35 applies heat and pressure to fix the transferred toner image on the recording medium P. The recording medium P is discharged onto the discharge tray 37 on the upper surface of the electrophotographic image forming apparatus 40 by the discharge roller pair 36.

  According to the present invention, even in the fixing member whose thermal conductivity is improved by blending carbon nanotubes in the elastic layer, the adhesiveness between the substrate and the elastic layer can be secured, so that the base can be used in the actual use environment. It is possible to suppress the interface peeling between the material and the elastic layer and to obtain a fixing member having sufficient durability.

  Hereinafter, the present invention will be more specifically described using examples.

<Preparation of Base Polymer 1>
As the base polymer 1, first, a side chain represented by the structural formula of the above-mentioned formula 1 as a silicone compound having a unsaturated aliphatic group in a side chain (first silicone compound, hereinafter also referred to as “Si-1”) A silicone compound was prepared in which the amount of vinyl groups in parts was 1.2% in terms of silicon atom ratio.
Next, as a silicone compound having an unsaturated aliphatic group at the end (a third silicone compound according to the present invention, hereinafter also referred to as “Si-3”), the end portion is represented by the structural formula of the formula 2 A silicone compound was prepared in which the amount of vinyl groups was 0.8% in terms of silicon atom ratio.
Furthermore, as the crosslinking agent silicone compound (the second silicone compound according to the present invention, hereinafter referred to as "Si-2"), R _{1 in} the structural formula of the formula 5 is a methyl group, and the amount of hydrosilyl group is A silicone compound was prepared in which 19.5% of the silicon atom ratio was introduced.
These were weighed at the compounding ratio shown in Table 1, and further, a trace amount of hydrosilylation catalyst (platinum catalyst: platinum carbonyl cyclovinyl methyl siloxane complex) and an inhibitor were added and thoroughly mixed to obtain a base polymer 1. The average molecular weight of each silicone compound, the introduced amount of functional groups, and the compounding ratio are shown in Table 1.

The measurement of the weight average molecular weight (Mw) is carried out using a gel permeation chromatography analyzer (GPC) (trade name: SC-8010 system; manufactured by Tosoh Corp.) having a differential refractometer (RI) as a detector (trade name) Shodex K-800D × 1 bottle, Shodex K-805L × 2 bottles; both manufactured by Showa Denko KK) were sequentially set, and chloroform (CHCl ₃ ) was used as an eluent. A GPC calibration curve of molecular weight and retention time was prepared in advance using plural kinds of polydimethylsiloxanes whose molecular weight is known, and the average molecular weight (Mw) was calculated from the elution curve of the silicone compound used this time.

The nuclear magnetic resonance apparatus (brand name: FT-NMR * AL400 type; Nippon Electronics Co., Ltd. make) was used for the measurement of the introduction amount of a functional group. Deuterated chloroform (CDCl ₃ ) is used as the solvent, and proton ( ¹ H) is observed in the hydrogen nucleus measurement (H-NMR) mode as an observation nucleus, the amount of unsaturated aliphatic groups in terminal and side chains and the hydrosilyl group The amount was quantified and calculated.

<Preparation of Base Polymers 2 to 7>
As the Si-1, Si-2 and Si-3, silicone compounds having the weight average molecular weight, the amount of unsaturated aliphatic group and the amount of hydrosilyl group having the values shown in Table 1 were mixed at the compounding ratio shown in Table 1 Base polymers 2 to 7 were prepared in the same manner as base polymer 1 except for the following.

Example 1-1
Carbon nanotube (trade name: VGCF; manufactured by Showa Denko KK, average fiber diameter 150 nm, average fiber length 8 μm) is added to the base polymer 1 as a thermally conductive filler so that the volume filling ratio is 2.0%. And further add alumina (trade name: Alna beads CB-A20S; manufactured by Showa Denko KK, average particle diameter: 21 μm) to a volume filling ratio of 35.0%, and sufficiently mix them to obtain a silicone rubber composition. I got one.

  A nickel electroformed endless sleeve having an inner diameter of 30 mm, a width of 400 mm and a thickness of 40 μm was prepared as a base material. During the series of manufacturing steps, the endless sleeve (endless sleeve) was handled by inserting the core therein.

  First, a primer (trade name: DY39-051A / B; Toray Dow Corning Co., Ltd.) is applied approximately uniformly on the outer peripheral surface of the substrate so that the dry weight is 30 mg, and the solvent is dried 160 Baking treatment was performed for 30 minutes in an electric furnace set at ° C.

  The silicone rubber composition 1 was applied to a thickness of 300 μm on the primer-treated substrate by a ring coating method. The obtained endless belt was heated in an electric furnace set at 200 ° C. for 4 hours to cure the silicone rubber to obtain an elastic layer.

  The elastic layer was irradiated with ultraviolet rays using an ultraviolet lamp installed at a distance of 10 mm from the surface while rotating the surface of the endless belt at a moving speed of 20 mm / sec in the circumferential direction. Irradiation was performed at 100 ° C. for 5 minutes in an air atmosphere using a low-pressure mercury ultraviolet lamp (trade name: GLQ 500 US / 11; manufactured by Toshiba Lighttech Co., Ltd. (old: Harison Toshiba Lighting Co., Ltd.)) as the ultraviolet lamp.

  After cooling to room temperature, add an addition-curable silicone rubber adhesive (trade name: SE1819 CV A / B; Toray Dow Corning Co., Ltd.) on the surface of the elastic layer of the endless belt to a thickness of about 20 μm. Applied approximately uniformly.

  Subsequently, a fluorine resin tube (trade name: KURANFLON-LT; manufactured by Kurashiki Spinning Co., Ltd.) having an inner diameter of 29 mm and a thickness of 20 μm was laminated. Thereafter, the belt surface was uniformly handled from the top of the fluorocarbon resin tube, and the excess adhesive was scraped out so as to be sufficiently thin from between the elastic layer and the fluorocarbon resin tube.

  The adhesive was cured by heating the endless belt for 1 hour in an electric furnace set at 200 ° C. to fix the fluororesin tube (surface layer) on the elastic layer. Both ends of the obtained endless belt were cut to obtain a fixing belt 1 having a width of 341 mm.

  An elastic layer is cut out from the fixing belt 1 in a size of 50 mm in length, 5 mm in width and 200 μm in thickness, and set to a tension measurement attachment of a dynamic viscoelasticity measuring apparatus (trade name: Rheogel-E4000; manufactured by UBM Co., Ltd.) The elastic modulus was measured at 50 ° C. and 200 ° C. at a frequency of 10 Hz.

  Further, the fixing belt 1 is set as shown in FIG. 2 by the method shown above, and a peeling test between the base material and the elastic layer is carried out, and a force gauge (trade name: digital force gauge FGX-5; Measurement of the adhesive strength (peeling strength) between the base material and the elastic layer and observation of the fractured surface were carried out according to Shinko Co., Ltd.). The respective results are shown in Table 3.

(Examples 1-2 to 1-5, comparative examples 1-1 to 1-2)
Silicone rubber compositions 2 to 7 were prepared in the same manner as the silicone rubber composition 1 according to Example 1, except that the base polymer 1 was changed to the base polymers 2 to 7. Then, fixing belts 2 to 7 were produced in the same manner as in Example 1 except that silicone rubber compositions 2 to 7 were used for forming the elastic layer, and evaluated in the same manner as in Example 1-1.
Further, a dumbbell-shaped No. 3 test piece for measurement of tensile strength was produced in the same manner as Example 1-1 except that silicone rubber compositions 2 to 7 were used, and the tensile strength was measured.
The measurement results are shown in Table 2 and Table 3.

(Example 2-1)
The fixing belt 1 according to this example was manufactured by the method described in Example 1-1. The fixing belt 1 was attached to a fixing device unit of a color laser printer (trade name: Satera LBP 5910; manufactured by Canon Inc.) under a pressure of 32 kgf.
The fixing device unit was mounted on the color laser printer. Using this color laser printer, the image quality stability test and the endurance test of the electrophotographic image described later were conducted.

  The evaluation methods of the image quality stability test and the durability test are as follows.

(Evaluation method of image quality stability test)
In a color laser printer equipped with a fixing belt, 100 sheets of image quality stability evaluation images are continuously fixed at an environment of a temperature of 10 ° C. and a humidity of 50% and an input voltage of 100 V. Paper is A4 size recycled paper (trade name: Recycled paper GF-R100; Canon Inc., thickness 92 μm, basis weight 66 g / m ² , waste paper content ratio 70%, Beck smoothness 23 seconds (according to JIS P8119) Using the same method.
An image quality stability evaluation image is an image in which the image identification number S6 color chart of "High-definition color digital standard image (XYZ / SCID)" (JIS X 9204: 2004) specified by Japanese Industrial Standards is placed near the center of the paper. It is.
The fused and mixed state of the toner was compared between the first sheet image and the 100th sheet image obtained at this time, and the sensory evaluation by five subjects was performed on the change in color tone. Evaluation results are displayed according to the determination criteria shown in Table 4 below.
In this test, the quality of the image quality stability evaluation image of the 100th sheet fixed by the fixing member in which heat is accumulated in the elastic layer by continuously fixing the image quality stability evaluation image of 100 sheets, Compare with the quality of the eye quality stability evaluation image.
If the development of the crosslinked structure in the elastic layer is not sufficient, heat is accumulated in the elastic layer as the elastic layer is heated as the fixing member is used, and the elastic modulus of the elastic layer is lowered. As a result, the quality is different between the first image quality stability evaluation image and the 100th image quality stability evaluation image fixed by the fixing member in which the elastic modulus of the elastic layer is lowered. That is, this evaluation is performed to evaluate the influence of the degree of development of the crosslinked structure of the elastic layer on the temperature dependence of the elastic modulus of the elastic layer.

(Evaluation method of durability test)
Using a color laser printer equipped with a fixing belt, used in the image quality stability test, cross-feeds A4 size recycled paper (paper similar to that used in the image quality stability test) and passes the sheet durability test Do. Evaluation results are displayed in accordance with the determination criteria shown in Table 5 below.

(Examples 2-2 to 2-5, comparative examples 2-1 to 2-2)
According to the methods described in Examples 1-2 to 1-5 and Comparative Examples 1-1 to 1-2, the fixing belts 2 to 2 according to Examples 2-2 to 2-5 and Comparative Examples 2-1 to 2-2 7 was produced.
The image quality stability test and the durability test were conducted in the same manner as in Example 2-1 except that these fixing belts were used.

  The evaluation results of Examples 2-1 to 2-5 and Comparative examples 2-1 to 2-2 are shown in Table 6 below.

  As described above, by using the present invention, in the fixing member containing carbon nanotubes in the elastic layer, the adhesiveness between the base material and the elastic layer is sufficiently ensured while securing the stability of the image quality. There is an industrial applicability that can provide a fixing member.

1 Fixing Belt 2 Fixing Roller 3 Base Material 4 Elastic Layer 5 Surface 11 Fixing Belt 12 Core 13 Force Gauge 14 Chuck

Claims (15)

A fixing member for electrophotography comprising a substrate, an elastic layer comprising a cured silicone rubber provided on the substrate, and a surface layer,
The elastic layer further comprises carbon nanotubes,
When the elastic modulus at 50 ° C. of the elastic layer is E50 and the elastic modulus at 200 ° C. of the elastic layer is E200, E200 / E50 is 0.5 or more and less than 1.0,
The peel adhesion strength between the elastic layer and the base material is 3.0 N / cm or more and 20.0 N / cm or less, and
A fixing member characterized in that the elastic layer is cohesively broken in a peeling test from the substrate. The fixing member is a fixing belt having a belt shape, and
The fixing member according to claim 1, wherein a thickness of the elastic layer is 100 μm or more and 500 μm or less. The fixing member is a fixing roller having a roller shape, and
The fixing member according to claim 1, wherein a thickness of the elastic layer is 300 μm or more and 10 mm or less. The elastic layer is formed by curing an addition-curable silicone mixture formed on the substrate,
The addition-curable silicone mixture is
A first silicone compound having in the side chain an unsaturated aliphatic group bonded to a silicon atom,
A second silicone compound having a hydrogen atom bonded to a silicon atom,
A third silicone compound terminated with an unsaturated aliphatic group bonded to a silicon atom,
The fixing member according to claim 1, comprising carbon nanotubes. The fixing member according to claim 4, wherein the first silicone compound has a structure represented by the following formula 3:

(In Formula 3, R ₁ represents a monovalent unsubstituted or substituted hydrocarbon group not containing an unsaturated aliphatic group. R ₂ represents an unsaturated aliphatic group. M is an integer of 0 or more, n represents an integer of 3 or more). The fixing member according to claim 5, wherein R _{2 in the} formula 3 is any one selected from a vinyl group, an allyl group, a 3-butenyl group, a 4-pentenyl group and a 5-hexenyl group. The fixing member according to claim 4, wherein the third silicone compound has a structure represented by the following formula 4:

(In Formula 4, R ₁ represents a monovalent unsubstituted or substituted hydrocarbon group containing no unsaturated aliphatic group. R ₂ represents an unsaturated aliphatic group. N represents a positive integer. ).   The fixing member according to claim 7, wherein n in the formula 4 is 200 or more and 1000 or less. A method of manufacturing the fixing member according to claim 1, wherein
Curing the layer of the addition-curable silicone mixture formed on the substrate,
The addition-curable silicone mixture is
A first silicone compound having in the side chain an unsaturated aliphatic group bonded to a silicon atom,
A second silicone compound having a hydrogen atom bonded to a silicon atom,
A third silicone compound terminated with an unsaturated aliphatic group bonded to a silicon atom,
A method of manufacturing a fixing member, comprising: carbon nanotubes. 10. The method of manufacturing a fixing member according to claim 9, wherein the first silicone compound has a structure represented by the following formula 3:

(In Formula 3, R ₁ represents a monovalent unsubstituted or substituted hydrocarbon group not containing an unsaturated aliphatic group. R ₂ represents an unsaturated aliphatic group. M is an integer of 0 or more, n represents an integer of 3 or more). 11. The fixing member according to claim 10, wherein R _{2 in the} formula 3 is any one selected from a vinyl group, an allyl group, a 3-butenyl group, a 4-pentenyl group and a 5-hexenyl group. Production method. 10. The method according to claim 9, wherein the third silicone compound has a structure represented by the following formula 4:

(In Formula 4, R ₁ represents a monovalent unsubstituted or substituted hydrocarbon group containing no unsaturated aliphatic group. R ₂ represents an unsaturated aliphatic group. N represents a positive integer. ).   13. The method according to claim 12, wherein n in the formula 4 is 200 or more and 1000 or less. A fixing device for fixing an unfixed toner image formed on a recording medium onto the recording medium, comprising:
A fixing member according to claim 1;
A fixing device comprising: a fixing member disposed opposite to the fixing member and forming a fixing nip with the fixing member. Electrophotographic photoreceptor,
A charging device for charging the surface of the electrophotographic photosensitive member,
An exposure unit for forming an electrostatic latent image on the electrophotographic photosensitive member;
An electrophotographic image forming apparatus comprising: an intermediate transfer member; and the fixing device according to claim 14.

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